The renin-angiotensin-aldosterone system (RAAS) plays a crucial role in the regulation of blood pressure. The RAAS cascade begins with the release of renin by the juxtaglomerular cells of the kidney into the circulation. Renin secretion is stimulated by several factors, including Na+ load in the distal tubule, β-sympathetic stimulation, and/or reduced renal perfusion. Active renin in the plasma cleaves angiotensinogen (produced by the liver) to angiotensin I, which is then converted by circulating and locally expressed angiotensin-converting enzyme (ACE) to angiotensin II. Most of the effects of angiotensin II on the RAAS are exerted by its binding to angiotensin II type 1 receptors (AT1R), leading to arterial vasoconstriction, tubular and glomerular effects, such as enhanced Na+ reabsorption or modulation of glomerular filtration rate. In addition, together with other stimuli such as adrenocorticotropin, anti-diuretic hormone, catecholamines, endothelin, serotonin, and levels of Mg2+ and K+, AT1R stimulation leads to aldosterone release which, in turn, promotes Na+ and K+ excretion in the renal distal convoluted tubule.
Dysregulation of the RAAS leading to, for example, excessive angiotensin II production and/or AT1R stimulation results in hypertension which can lead to, e.g., increased oxidative stress, promotion of inflammation, hypertrophy, and fibrosis in the heart, kidneys, and arteries, and result in, e.g., left ventricular fibrosis, arterial remodeling, and glomerulosclerosis.
Hypertension is the most prevalent, controllable disease in developed countries, affecting 20-50% of adult populations. It is a major risk factor for various diseases, disorders and conditions such as, shortened life expectancy, chronic kidney disease, stroke, myocardial infarction, heart failure, aneurysms (e.g. aortic aneurysm), peripheral artery disease, heart damage (e.g., heart enlargement or hypertrophy) and other cardiovascular related diseases, disorders and/or conditions. In addition, hypertension has been shown to be an important risk factor for cardiovascular morbidity and mortality accounting for, or contributing to, 62% of all strokes and 49% of all cases of heart disease.
Despite the number of anti-hypertensive drugs available for treating hypertension, more than two-thirds of subjects are not controlled with one anti-hypertensive agent and require two or more anti-hypertensive agents selected from different drug classes. This further reduces the number of subjects with controlled blood pressure as compliance and side-effects increase with increasing medication.
Accordingly, there is a need in the art for alternative therapies and combination therapies for subjects having an angiotensinogen-associated disease.